In order to estimate an attitude of a projector (and a camera), it has been necessary to determine corresponding points between the projector (projection image) and the camera (captured image). In order to detect the corresponding points between the projector and the camera, it is necessary to capture the image to be projected by the projector with the camera. In a case of a still image (pattern image or still image picture), the same picture is continuously projected, whereby a desired image can be captured, and the corresponding points can be detected even in a case where an imaging timing is random.
For example, with respect to on-line sensing, which is a technique for determining corresponding points while projecting images of a content or the like, corresponding points can be detected while input pictures are projected, whereby a picture presentation position can be updated to a correct picture presentation position even in a case where an attitude of the projector changes due to an external disturbance (see Patent Document 1).